JP2021505761A - Steel composites, methods for manufacturing parts, and uses - Google Patents

Abstract

The present invention comprises at least one first layer (1, 3) formed of machinable and / or shearable steel and a steel that is integrally coupled to and formable in the first layer. It relates to a steel composite having at least one second layer (2, 4) formed and at least two layers (1, 2, 3, 4) including. [Selection diagram] Fig. 1

Description

The present invention relates to a steel composite having at least two steel layers. The present invention further relates to a method for manufacturing a part and the use of this part.

In the area of automobiles, such as automobile drivetrains, for accuracy and / or surface requirements, multiple parts to be processed by material removal techniques are used.

Conventional techniques disclose a plurality of steels from which the material can be removed and / or which can be sheared. For most parts, these steels are mainly from semi-finished products, which are usually columnar and specially used for the production of rotatable symmetric parts, their final geometry. It is provided by subjecting the semi-finished product, which is in the form of a solid material, to a rotary processing operation to remove the material until the shape is formed. Processing in this mode is very important and costly.

To reduce material input, at least, material-removable and / or shearable steels are usually formed from the two-dimensional product, and these steels are processed mechanically or by material removal. Preliminary geometry can be given before the final geometry is generated. Multiple steels with good material removability and / or shearability generally have poor forming properties of the alloy components that allow good material removability, such as lead, This is because phosphorus and / or sulfur inhibits the formability. A plurality of steels are used that have good formability but do not exhibit the desired material removal properties and form so-called continuous chips. The advantage in forming continuous inserts is that the continuous inserts can damage the surface of the workpiece to be treated. In addition, tools that remove material are blocked as a result, which can increase cleaning complexity and thus increase processing time. The service life of tools that remove this material can also be shortened.

Therefore, an object of the present invention is to provide a semi-finished product that combines the above-mentioned plurality of contradictory properties, and as a result, to compensate or reduce the above-mentioned disadvantages.

This object is achieved by a steel composite having the technical features of claim 1.

In close contact with at least one first layer of material-removable and / or shearable steel in order to combine the contradictory properties described above in the semi-finished product. A steel composite having at least one second layer of formable steel and at least two layers comprising the steel composite is proposed. The steel composites of the present invention guarantee good formability coupled with good material removeability and / or shearability.

Steel from which material can be removed and / or shearable is specifically understood to mean free-cutting steel (EN10087). It is also possible to use steel for cooling and heating (EN10083), calcined steel (EN10084), or nitrided steel (EN10085), each having a sulfur content of at least 0.01% by weight.

The formable steel is specially defined as a steel having a quality of DC (DIN EN 10130), DD (DIN EN 10111) or DX (DIN EN 10346), or a fine-grained structural steel for cooling formation. Understood. It is also possible to use thermally specially formable steels so that the required final geometry of the part to be manufactured can be modeled without failure.

In the first embodiment, the at least one first layer of the steel composite is, for example, in addition to Fe and unavoidable impurities from the production.
C up to 0.60% by weight and
Si up to 1.00% by weight and
Mn up to 2.00 wt% and
With P up to 0.150% by weight,
S up to 0.50% by weight and
With Pb up to 0.50% by weight,
Consists of
ΣP + S + Pb ≧ 0.020% by weight is satisfied,
The first layer above
Selective Cr up to 3.0%,
Selective Cu up to 0.50%,
Selective Nb up to 0.050%,
Selective Mo up to 1.0%,
Selective N, up to 0.020%
Selective Ti up to 0.020%,
Selective V up to 0.40%,
Selective Ni, up to 5.0%
Selective B up to 0.010%,
Selective Sn, up to 0.050%
Selective H, up to 0.0010%
Selective As, up to 0.020%
Selective Co, up to 0.020%
Selective O, up to 0.0050%
Selective Ca up to 0.0150% and
Selective Al up to 1.0%,
It may contain one or more of the selective alloying elements.

C is a reinforced alloy element and contributes to an increase in hardness as its content increases because C decomposes in austenite as an interstitial atom or is selectively selected for Fe or the above alloys. Because it forms a carbide with Cr, Ti, Nb and / or V contained in, on the one hand, it can be harder than the surrounding matrix, or at least distorts the matrix, increasing the hardness of the matrix. is there. Therefore, in order to achieve or establish the desired hardness and to guarantee a particular resistance for mechanical processing, C contains at least 0.020% by weight, especially at least 0.070% by weight. , Preferably present in a content of at least 0.10% by weight. The content of C is limited to a maximum value of 0.60% by weight, particularly a maximum value of 0.55% by weight.

Si is an alloying element that can contribute to solid solution curing, and according to its content, has a useful effect in increasing hardness, and has a content of at least 0.020% by weight, particularly at least 0.050% by weight. % Content can be present. If the content is lower than this, the effect of Si cannot be clearly detected. However, Si also has no adverse effect on the properties of steel. This has a detrimental effect on formability and durability if too much silicon is added to the steel. Therefore, in order to guarantee particularly sufficient rollability, this alloying element has a maximum value of 1.00% by weight, particularly a maximum value of 0.60% by weight, preferably a maximum value of 0.40% by weight. Limited to. Furthermore, Si can be used for the reduction of steel, for example, where selective use of Al should be avoided in order to prevent unwanted bonds, such as unwanted bonds of N.

Mn is an alloying element that can contribute to curability and is particularly used to combine S to give MnS, with a content of at least 0.20% by weight, particularly at least 0.40% by weight. The quantity can be present. Manganese reduces the critical cooling rate, which can increase curability, especially in heat treatments. In order to ensure good forming properties, this alloying element is limited to a maximum value of 2.00% by weight, in particular a maximum value of 1.50% by weight. Furthermore, Mn has a significant separating effect and is therefore preferably limited to a maximum value of 1.30% by weight.

P is an iron-accompanying element having a remarkable effect of reducing durability, and is generally included in an undesired accompanying element. P can lead to significant separation due to its low diffusion rate for melt solidification. For these given reasons, this element is limited to a maximum value of 0.150% by weight, especially a maximum of 0.110% by weight.

S in steel has a significant tendency towards separation and forms an undesired FeS, for which reason it can be bound by Mn contained in the alloy. The content of S is therefore limited to a maximum value of 0.50% by weight, particularly a maximum of 0.45% by weight.

Pb can be contained in the alloy up to a maximum value of 0.50% by weight, particularly a maximum value of 0.40% by weight, preferably a maximum value of 0.350% by weight, which is mechanical. It can lead to the smooth surface of the steel in the process. Alloy content above the above limits will lead to legal excesses.

Preferably, at least one of the alloying elements S, P, Pb has a useful effect on the material removability by the formation of brittle inclusions in steel such that the chip breaks mechanically or in a material removal process. Thanks to this, at least 0.020% by weight, especially at least 0.050% by weight, preferably 0., individually or in total of S and P, S and Pb, P and Pb, or S, P and Pb. It is present at 10% by weight. Correspondingly, in total, ΣP + S + Pb ≧ 0.020% by weight holds.

Cr as a selective alloying element can contribute to the establishment of strength, depending on its content, especially with a content of at least 0.020% by weight. In addition, Cr can be used alone or in combination with other elements as a carbide-forming product. Due to its useful effect on the durability of the material, the Cr content can preferably be adjusted to at least 0.150% by weight. For economic reasons, this alloying element can be limited to a maximum value of 3.0% by weight, in particular a maximum of 2.50% by weight, preferably a maximum of 2.0% by weight.

Cu, as a selective alloying element, can contribute to an increase in hardening due to precipitation hardening, and can be particularly contained in the alloy with a content of at least 0.010% by weight. Cu can be limited to a maximum of 0.50% by weight.

Ti, Nb and / or V may be included in the alloy as selective alloying elements individually or in combination for grain refinement. In addition, Ti can be used for binding N. However, in particular, these elements can be used as microalloy elements to form reinforced carbides, nitrides and / or carbonitrides. To ensure these effects, Ti, Nb and / or V can be used with a content of at least 0.010% by weight, either individually or as a whole. For a perfect bond of N, the Ti content should be at least 3.42 x N. Nb is limited to a maximum value of 0.050% by weight, especially to a maximum value of 0.030% by weight, and Ti is limited to a maximum value of 0.020% by weight, especially to a maximum value of 0.0150% by weight. And V is limited to a maximum value of 0.40% by weight, especially to a maximum of 0.250% by weight, because higher content can have adverse effects on material properties. This is because it can have an adverse effect on the durability of the first layer.

Mo may be selectively included in the alloy as a carbide formation in order to increase the yield point and improve durability. In order to guarantee the efficacy of these effects, the alloy can contain at least 0.010% by weight. For cost reasons, its maximum content is limited to a maximum value of 1.0% by weight, preferably a maximum of 0.70% by weight.

N as a selective alloying element has a similar effect because its ability to form nitrogen has a useful effect on strength. In the selective presence of Al, aluminum nitride is formed, which improves nucleation and prevents higher grain growth. Its content is limited to a maximum of 0.020% by weight. In the case of the selective presence of Ti, which has an adverse effect on durability, the option of establishing a maximum content of 0.0150% by weight is given to avoid the unwanted formation of coarse titanium nitride. Furthermore, when boron, the selective alloying element, is used, boron is bound by nitrogen if the content of aluminum or titanium is not too high or absent.

Ni can be selectively included in the alloy up to a maximum value of 5.0% by weight, but can have a useful effect on the affordability of the material. For cost reasons, a content of 4.50% by weight or less, preferably 4.30% by weight or less, is established.

B, a selective element in atomic formation, causes microstructural transformation to ferrite / bainite, especially when N is bonded by selectively strong nitride formations such as Al and / or Nb. It can be delayed and the strength can be improved, and this B can be present, especially with a content of at least 0.0055% by weight. This alloying element is limited to a maximum value of 0.010% by weight, especially to a maximum value of 0.0007% by weight, because higher content adversely affects the properties of the material, especially. This is because it can have durability at the grain boundaries.

Sn, As and / or Co are selective alloying elements that can be included in impurities to establish specific properties, either individually or in combination, when they are not intentionally included in the alloy. is there. Its content is up to the maximum value of Sn of 0.050% by weight, especially up to the maximum value of Sn of 0.040% by weight, up to the maximum value of Co of 0.020% by weight, and 0.020. It is limited to the maximum value of As, which is% by weight.

O is selective and usually undesirable, but is particularly separated between the first layer and the second layer, as described, for example, in the German Patent Application Publication No. 102016204567A1. Oxide coatings in the layers intentionally prevent diffusion between different alloy steels, which can benefit in very low content in the present invention. The maximum oxygen content is described as 0.0050% by weight, preferably 0.0020% by weight.

H is selective and, as the smallest atom, highly mobile between multiple intermediate lattice sites in steel and can lead to crevices in the core from hot rolling to cooling in particular. This element, hydrogen, is therefore up to a maximum value of 0.0010% by weight, particularly up to a maximum value of 0.0006% by weight, preferably up to a maximum value of 0.0004% by weight, even more preferably. It is reduced to a maximum of 0.0002% by weight.

Ca selectively in the melt of the alloy as a desulfurizing agent due to its controlled effect on sulfide levels at content up to 0.0150% by weight, preferably up to 0.0050% by weight. It can be included, which leads to the altered plasticity of the sulfide in hot rolling. Furthermore, the addition of Ca preferably improves the cooling formation property. Such an effect is effective above a content of 0.0005% by weight, and this limitation can therefore be selected as the minimum value in the case of selective use of Ca.

Al can, in particular, contribute to the reduction, and therefore a content of at least 0.010% by weight can be selectively established. This alloying element is limited to a maximum value of at least 1.0% by weight to ensure maximum castability, preferably in the form of a non-metal oxide-containing material that can adversely affect the properties of the material. Undesirable precipitates in the material in, are limited to a maximum of 0.3% by weight to reduce and / or avoid. For example, its content is set between 0.020% by weight and 0.30% by weight. Al can also be used for the purpose of binding nitrogen selectively present in steel.

In one embodiment, the at least one second layer in the steel composite is elongated at a break of A ₈₀ > 10, particularly at a break of A ₈₀ > 15, preferably A _80. It consists of steel with elongation at breaks of> 20, more preferably A ₈₀ > 25.

In one embodiment, the first layer is a material thickness between 5% and 70%, particularly a material thickness between 10% and 50%, based on the total material thickness of the steel composite. Has a material thickness between 20% and 40%. The material thickness of the first layer, at least 5%, is intended to ensure that the mechanical treatment can be performed exclusively in the first layer. The material thickness of the first layer is limited to a maximum of 70%, which is intended to give the steel composite a particular formability. The total material thickness is between 0.5 mm and 20.0 mm, particularly between 1.0 mm and 15.0 mm, preferably between 2.0 mm and 10.0 mm. In the simplest embodiment, the steel composite has exactly one first layer and one second layer. According to the present application, the steel composite may also have at least three layers, in which case the first layer is of two outer layers, each of which is formed from the second layer. In between, it can be arranged as a core layer. Alternatively, the second layer may be arranged as a core layer between the two outer layers, each of which is formed as the first layer. These outer layers in the embodiment of at least three layers described above may have either a symmetric structure or an asymmetric structure.

In a further embodiment, the steel composite has been produced by cladding, especially by roll cladding, preferably by hot roll cladding, as described, for example, in German Patent No. 10200500606B3. References are made to this specification and the contents of this specification are incorporated into this application. The production of composites is a general prior art.

In a second aspect, the present invention relates to a method for producing a composite, in which case the steel composite of the present invention is provided, formed in a preformed shape and particularly cooled. In the region of the first layer, at least a plurality of parts are mechanically processed to produce a final shape, or a further shape specifically for a further processing step. Mechanical processing is specifically understood to mean processing to remove material, such as lathe work, cutting and / or drilling, at multiple portions in the area of the first layer. By arranging the first layer in the component, for example as an accessible layer, it is possible to remove essentially perfect material on the surface. If the first layer is only partially accessible when arranged as the core layer in the component, for example in at least three layer embodiments, the first layer is the end face of the component. It can actually be processed by removing the material only in the area.

In one embodiment of the method, the final shape or the further shape can be heat treated. The heat treatment can be combined with stress relief annealing or hardening, optionally in combination with tempering or surface hardening in subsequent carburizing or nitriding, to establish additional or improved properties in the part.

In a second aspect, the present invention relates to the use of parts manufactured by any one of the above methods as parts in an automobile structure or metal structure, particularly in an automobile drivetrain. The drivetrain of an automobile contains all the parts that transmit the power of the engine to the wheels. These include engines, clutch assemblies, transmissions, powertrains, drive shafts and differentials. In hybrid vehicles in the case of full hybrids and plug-in hybrids, as well as in pure electric vehicles, electric motors are included. Exemplary components can be disc supports, rotor supports, stator supports, pressure plates, timing belt pulleys, encoder wheels, rotor wheels and shafts.

Preferably, the use relates to all rotationally symmetric parts that should still be treated by material removal in at least a plurality of portions after being formed without material removal.

Hereinafter, the present invention will be specifically described with reference to drawings showing a number of useful examples. The same parts are usually labeled with the same reference numerals.

FIG. 1 shows a first useful example of a component of the invention having various designs. FIG. 2 shows a second useful example of a component of the invention having various designs. FIG. 3 shows a third useful example of a component of the invention having various designs.

A plurality of commercially flat steel products can be used together with a particular selection to produce the steel composites of the present invention by hot roll cladding, which in particular have a plurality of conflicting properties. For example, it is an object of the present invention to produce a semi-finished product capable of combining good material removability and / or sufficient formability combined with shearability. For this purpose, a plurality of sheet metal blanks and / or a plurality of slabs comprising at least two layers (1, 2, 3, 4) having different properties, one of which is placed on top of the other. In addition, they are deposited and further adhered to each other, at least in the region along their edges, preferably welded together to give a preliminary composite. This preliminary composite is exposed to a temperature of at least 1000 ° C and is further hot rolled in a number of steps to give a steel composite with a total material thickness of, for example, 2.0 to 10.0 mm. .. If desired, the steel composite can be thinned to an even thinner total material thickness, especially by cold rolling.

FIG. 1 shows the first useful aspect of the novel part (10) from the perspectives of a plurality of different perspectives, namely, an oblique perspective, a cross section according to the I-I cut plane, and an enlarged cross section. An example is shown. The part (10) is made of a steel composite that is manufactured according to the hot roll cladding operation described above and comprises a first layer (1) and a second layer (2) that are closely bonded to each other. It is formed. The first layer (1) is made of steel with good material removability and / or shearability, and the second layer (2) is made of steel with good formability. The first layer (1) can be made of, in particular, free-cutting steel according to EN10087, such as steel with the 11SMn30 designation, or has a sulfur content of at least 0.01% by weight. It can consist of steel for cooling and heating according to EN10083, for example steel with 42CrMoS4 designation. The second layer (2) is a steel with elongation at breaks A ₈₀ > 10, especially A ₈₀ > 15, eg DC designation according to DIN EN 10130, DD designation according to DIN EN 10111, DIN It may consist of steel with a DX designation according to EN 10346 or an S355 MC designation according to DIN EN 10149-2.

An essential two-dimensional steel composite for the manufacture of part (10), i.e. a two-dimensional steel composite having a material thickness of at least 25% based on the total material thickness of the steel mixture, has been provided. Due to the higher percentage of steel with good formability (second layer 2), sufficient and complex formation can be guaranteed. The steel composite is cooled and formed into a preformed shape by an appropriate forming means (not shown), and the surface of the preformed shape is formed into a final shape by a single side material removal treatment by an appropriate means (20). Alternatively, it was transformed into a further shape for further processing steps. Alternatively, the steel composite can be heat-formed, if necessary, for the production of preformed shapes. By removing the material, the material thickness of the first layer (1) was reduced to less than half of the original material thickness of the first layer (1) before mechanical treatment. The mechanical treatment does not have to be applied completely over the entire surface area of the first layer (1), but can only be performed on a plurality of required parts. After the mechanical treatment, heat treatment may also be performed on the final shape or on the further shape in order to improve the plurality of properties.

FIG. 2 shows the second usefulness of the novel part (10') from the perspectives of a plurality of different perspectives, namely, an oblique perspective, a cross section according to the II-II cut plane, and an enlarged cross section. An example is shown. The part (10') is formed of a three-layer steel composite as compared to the part (10). The steel composite comprises a second layer (2) arranged as a core layer, each between two outer layers formed from the first layer (1, 3).

Two second layers (1, 3), each having a material thickness of at least 20% based on the total material thickness of the two-dimensional steel composite, i.e., essential for the manufacture of the part (10'). A two-dimensional steel composite containing) was provided. The steel composite is cooled and formed into a preformed shape by an appropriate forming means (not shown), and this preformed shape, or more specifically, two surfaces of the first layer (1, 3) are suitable. By means (20), the material was removed on both sides for the production of the final shape or further shape. Alternatively, the steel composite can be heat-formed, if necessary, for the production of preformed shapes. Reduced material thickness by about 1/4 of the original material thickness of the first layer (1, 3) prior to mechanical processing to meet accuracy and / or surface requirements for the entire part (10'). Material removal was then applied to both sides. The mechanical treatment need not be applied completely over the entire surface of the first layer (1, 3), but can only be performed on a plurality of required parts. After the mechanical treatment, heat treatment may also be performed on the final shape or the further shape in order to improve the plurality of properties.

FIG. 3 shows a third of the novel parts (10 ″) from multiple different perspectives, namely, an oblique perspective, a cross section according to the III-III cut plane, and an enlarged cross section. Here is a useful example. The part (10 ″) is formed of a three-layer steel composite, similar to the part (10 ′), with the first layer (1) being the second layer (2, 4), respectively. The difference is that it is arranged as a core layer between the two outer layers formed from.

Containing two first layers (1) having a material thickness of at least 50% based on the total material thickness of the steel mixture, that is, a two-dimensional steel composite essential for the manufacture of the part (10 ″). A two-dimensional steel composite was provided. The steel composite is cooled and formed into a pre-shape by a suitable forming means (not shown), and the pre-shape is mechanically formed from its end face by a suitable means (20) for the formation of the final shape. In the end face, the part (10 ″) was introduced with a geometric shape over the outer circumference in the shape of a groove. Alternatively, the steel composite can be heat-formed, if necessary, for the production of preformed shapes. After the mechanical treatment, heat treatment may be performed on the final shape to improve the plurality of properties.

The present invention is not limited to the various embodiments described above, and the individual features may be combined with each other as desired. More preferably, the parts of the present invention, or parts that can be manufactured from the steel composite of the present invention, are as one part in an automobile structure or a metal structure, particularly as one part in an automobile drive train. , Preferably as a form of rotating symmetric component.

Claims (8)

A steel composite having at least two layers (1, 2, 3, 4).
With at least one first layer (1, 3) of steel from which the material can be removed and / or sheared,
With at least one second layer (2, 4) of formable steel that is closely bonded to the first layer (1, 3).
A steel composite material comprising. The at least one first layer (1, 3) is in addition to Fe and impurities that are unavoidable from production.
C up to 0.60% by weight and
Si up to 1.00% by weight and
Mn up to 2.00 wt% and
With P up to 0.150% by weight,
S up to 0.50% by weight and
With Pb up to 0.50% by weight,
Consists of
ΣP + S + Pb ≧ 0.020% by weight is satisfied,
The first layer (1, 3)
Selective Cr up to 3.0%,
Selective Cu up to 0.50%,
Selective Nb up to 0.050%,
Selective Mo up to 1.0%,
Selective N, up to 0.020%
Selective Ti up to 0.020%,
Selective V up to 0.40%,
Selective Ni, up to 5.0%
Selective B up to 0.010%,
Selective Sn, up to 0.050%
Selective H, up to 0.0010%
Selective As, up to 0.020%
Selective Co, up to 0.020%
Selective O, up to 0.0050%
Selective Ca up to 0.0150% and
Selective Al up to 1.0%,
The steel composite according to claim 1, which may contain one or more of the selective alloying elements. The steel material according to claim 1 or 2, wherein the at least one second layer (2, 4) is made of a steel having an elongation at a break of A ₈₀ > 10, particularly an elongation at a break of A ₈₀ > 15. Complex. The first layer (1, 3) has a material thickness between 5% and 70%, particularly between 10% and 50%, based on the total material thickness of the steel composite. , The steel composite according to any one of claims 1 to 3. The steel composite according to any one of claims 1 to 4, which is produced by cladding, particularly hot roll cladding. A method for manufacturing parts (10, 10', 10'')
The steel composite according to any one of claims 1 to 5 is provided.
The steel composite is preformed and
A method characterized in that the pre-shape is mechanically processed in at least a plurality of portions in the region of the first layer (1, 3) to produce a final shape or a further shape. The method of claim 6, wherein the final shape or the further shape is heat treated. Use of parts manufactured in accordance with claim 6 or 7 in automobile structures or metal structures, especially in automobile drivetrains.

Images